7 Best Places to Find a Cofounder for a Climate Tech Startup (2026)

Climate communities, fellowships, a venture builder and climate weeks: what each costs, when it runs, and what to test before you commit

By Founder Compass · Updated 26 October 2026

At a glance

Costs and dates: each organisation's own page, 26 October 2026.

Why is a climate tech cofounder harder to find?

Three reasons, and they shape where you should look.

• Long timelines. Many climate companies involve hardware, chemistry, energy or land, so the road to revenue is longer than for a typical software startup. You need someone who is ready to stay for years, not months.
• Technical depth on both sides. Carbon13, a climate venture builder, asks applicants to pick one of four founder types: technical (science or engineering), technical (software, data or ML), commercial, or "venture catalyst" (Carbon13). A climate team often needs more than one of these.
• A smaller pool. General cofounder platforms aren't built around climate, so much of the search happens in climate communities, courses and events. That's what this list covers.

1. Foundinity: matched on commitment and how you work

A climate company can take years to earn much, so fit matters more: two people with the same ambition and staying power. Foundinity matches on exactly that kind of fit.

What it is: a cofounder matching platform for people looking for a cofounder, technical and non-technical. It's online and works wherever you are.

How it works:

• Preferences + a deeper assessment. You state your preferences, then an assessment captures how you work: working style, ambition, commitment, vision, values and personality, alongside skills. A multi-trait algorithm "built on established psychological compatibility models" ranks the result, so you see compatible people instead of hundreds of random profiles.
• Compatibility breakdown. Every match shows where you align and where you differ, so a gap in commitment or ambition shows up before you've spent a year on a pilot together.
• A 10-day clock on every match. The clock turns matches into calls instead of chats that sit unanswered. You book intro calls right where you match.
• Private by default. Your profile isn't public, and only compatible members can see it. That helps if you still work at an energy company or a lab and would rather not search in public.

Cost (checked Oct 2026): free to get started: 5 likes a week, up to 3 active matches and up to 3 profile saves. Plus is $5 a week or $15 a month (₹300 / ₹1,000 in India): 15 likes a week, unlimited active matches, everyone who liked you, the full compatibility score and breakdown, and up to 5 profile saves.

Best for: anyone starting a climate company who wants a partner with the same commitment and staying power, and who'd rather spend a weekly like on a compatible person than send dozens of cold messages.

Try Foundinity

2. Work on Climate: the #role-founders channel

Work on Climate is a Slack community run as a US non-profit, describing itself as "an action-oriented community for people serious about working in climate long-term". There's no matching; you post and search yourself.

• Watch-outs:
  • It's built for everyone working in climate, so cofounder posts sit among job and career talk.
  • Size figures vary by source and none come from its own page; judge it by how active the channels are when you join.
• How to use it: its climate entrepreneurship starter pack points to #role-founders as "a place for you to find cofounders and share opportunities". Post a short note on the problem, your skills, the skills you need and your weekly hours.
• Cost (checked Oct 2026): no fee listed; you get a Slack invite after a three-minute intake survey.
• Best for: a first, free place to post and to see what other climate founders are building.

3. Climatebase Fellowship: a course with a founder track

Climatebase runs a "12-week, industry-oriented educational program" with a year of community membership included. It's a course first, but its FAQ says founders can "share your startup idea and find co-founders and collaborators".

• Watch-outs:
  • It runs on fixed cohort dates. The latest, Cohort 10, runs from mid-September to 5 December 2026, so the next chance to join is a later intake.
  • The FAQ doesn't list the fee. It says 55% of past Fellows received some need-based financial aid.
  • For most Fellows it's a learning and career programme; founder support is one part of it.
• What founders get: entrepreneurship sessions, feedback from climate founders and investors, online Demo Days at the end of the cohort, and merit-based scholarships for some founder applicants.
• Schedule: live sessions run weekdays 9am to 1pm Pacific and are recorded, so attending live isn't required.
• Best for: watching how people work on a climate idea for 12 weeks before you ask them to join.

4. Terra.do: climate courses with a #founders channel

Terra.do is a climate education company. Its 12-week "Learning for Action" fellowship is fully online at 6 to 10 hours a week, and members get a year of community access.

• Watch-outs:
  • It's built around learning and careers; there's no cofounder matching, and the page doesn't list course prices.
  • Its founder numbers are its own: it says it has "200+ founders" among "7,000+ fellows".
• How to use it: the community has a #founders Slack channel. Its job board, which it says lists "65,000+ climate jobs", has also carried venture-builder cofounder roles, such as a Carbon13 listing.
• Cost (checked Oct 2026): prices not listed on its homepage; need-based scholarships are offered.
• Best for: people moving into climate from another field, who want to learn the domain and meet founders at the same time.

5. MCJ Collective: an application-only climate network

MCJ Collective grew out of climate podcast discussions in 2019 and now runs a member network for "tech and industry leaders who are building, working for, or advising on solutions" to climate change.

• Watch-outs:
  • Everyone applies, and applications are reviewed by hand; the page says it favours people with a clear reason to be active.
  • The join page doesn't list a price or a cofounder channel.
• What you get: a Member Hub, a Slack workspace and what it calls "hundreds of events".
• Best for: experienced operators, engineers and industry people, where you're likely to meet a partner with years in energy, buildings, industry or finance.

If your idea is in carbon removal, AirMiners is a narrower option: a carbon removal community of about 2,900 people (its own figure) with a five-week Learn course and a Launchpad accelerator for early-stage carbon removal founders.

6. Carbon13 Venture Builder: a programme built for team formation

Carbon13 is a climate venture builder in Cambridge, UK. Its venture builder is for people who "don't have a startup yet but want to find a co-founder". You join as an individual, and the first phase is spent forming a team.

• Watch-outs:
  • Phase 1 (Teaming) lasts ten weeks and has a "mandatory in-person component". You don't need to live in Cambridge or the UK, but you need to travel.
  • Only founders who form a team in Phase 1 move on to Phase 2.
  • Its own page gives two lengths: "five-month" in the intro and "over eight months" in the phase breakdown. Check the current cohort's dates.
  • The Berlin programme's last cohort has finished; Carbon13 says it is preparing a first programme from Amsterdam, with a waiting list.
• How it works: a cohort of about 80 people, guidance on what a good cofounder looks like, and the choice left to you: "the decision is yours to make". Carbon13 says its average cohort age is 37 and a third of members hold PhDs (its own figures).
• Cost (checked Oct 2026): no participation fee listed on the programme page. Read the programme's terms before you apply.
• Best for: scientists, engineers and operators ready to go full-time, who want a structured way to meet a cofounder.

7. Climate weeks and cofounder speed-meeting events

Climate weeks are city-wide weeks of hundreds of independent events. For a cofounder search, they're a concentrated meetup season.

• Climate Week NYC is organised by the non-profit Climate Group. It reports "1,500+ events, 120,000+ participants" (its own figures). The next one runs 19 to 26 September 2027.
• SF Climate Week calls itself "a decentralized climate gathering organized by and for the community", run by Climatebase and the Climate Week Network. The 2026 edition ran 18 to 26 April; the 2027 calendar "will go live in January 2027". It lists 750+ events (its own figure).
• Cofounder speed-meeting mornings appear around these weeks. C2FM, a New York climate founder community, ran one before Climate Week NYC: ten five-minute conversations, a yes or no after each, and an introduction when both say yes. Members-only by default, but that event was open to non-members on approval. C2FM says it has supported six founding team formations so far (its own figure).
• Watch-outs: each city runs once a year, every event registers separately (some need approval), and five minutes shows chemistry, not how someone works.
• Best for: meeting climate people face to face, especially if your company will need local pilots or partners.

What to test before you commit to a climate cofounder

Test these early; climate companies ask more of a partnership than most.

1. Timeline and runway. Ask how many years each of you can give before the company has to pay you, and what happens if a pilot takes twice as long. If one of you expects a quick software exit and the other a ten-year hardware build, stop there.
2. Technical depth, both ways. Use Carbon13's four founder types as a checklist: science or engineering, software or data, commercial, and someone who pulls it all together. Name which you are and which you need. For non-technical founders, the Enduring Planet interview suggests postdocs as a source of technical partners (Enduring Planet). Our guide to the best places to find a technical cofounder covers more routes.
3. A substantial project together. The same interview advises doing a real project together before signing anything, to see how the other person handles stress, and agreeing in advance to pay them fairly for their time.
4. Where you need to be. Pilots, labs and site visits may need one of you on the ground. If you'll work apart, read our guide to remote cofounders.
5. Why climate. Ask what each of you would do if the first market fails. A shared mission helps; a shared view of how to earn money from it matters as much.

If your climate idea is AI-led, our guide to finding a cofounder for an AI startup covers that side.

Sources (read 26 October 2026): Foundinity · Work on Climate: About · Work on Climate: Climate entrepreneurship starter pack · Climatebase Fellowship: structure and timeline · Climatebase: what the Fellowship offers entrepreneurs · Climatebase: financial aid · Terra.do · Terra.do job board: Carbon13 cofounder listing · MCJ Collective: Join · AirMiners · Carbon13 · Carbon13 Venture Builder Cambridge · Carbon13 Venture Builder Berlin · Climate Week NYC · SF Climate Week · C2FM: (pre)NY Climate Week Founder Speed Matching · Enduring Planet: Finding the perfect co-founder for your climate startup · YC Co-Founder Matching · YC ClimateTech Co-Founder Meetup (2022). Self-reported numbers are each organisation's own and undated unless stated.